Source/JavaScriptCore/bytecode/BytecodeLivenessAnalysis.h

/*
 * Copyright (C) 2013 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
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 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 */

#ifndef BytecodeLivenessAnalysis_h
#define BytecodeLivenessAnalysis_h

#include "BytecodeBasicBlock.h"
#include <wtf/FastBitVector.h>
#include <wtf/HashMap.h>
#include <wtf/Vector.h>

namespace JSC {

class CodeBlock;
class FullBytecodeLiveness;

class BytecodeLivenessAnalysis {
public:
    BytecodeLivenessAnalysis(CodeBlock*);
    
    bool operandIsLiveAtBytecodeOffset(int operand, unsigned bytecodeOffset);
    FastBitVector getLivenessInfoAtBytecodeOffset(unsigned bytecodeOffset);
    
    void computeFullLiveness(FullBytecodeLiveness& result);

private:
    void compute();
    void runLivenessFixpoint();
    void dumpResults();

    void getLivenessInfoForNonCapturedVarsAtBytecodeOffset(unsigned bytecodeOffset, FastBitVector&);

    CodeBlock* m_codeBlock;
    Vector<RefPtr<BytecodeBasicBlock> > m_basicBlocks;
};

inline bool operandIsAlwaysLive(CodeBlock*, int operand);
inline bool operandThatIsNotAlwaysLiveIsLive(CodeBlock*, const FastBitVector& out, int operand);
inline bool operandIsLive(CodeBlock*, const FastBitVector& out, int operand);

FastBitVector getLivenessInfo(CodeBlock*, const FastBitVector& out);

} // namespace JSC

#endif // BytecodeLivenessAnalysis_h